To CNC? Or not to CNC?

[Cory]

Originally Posted by cmaccoy

If i were you I'd just get a small CNC mill. Like one of those cheap things some schools get for like 4 thousand dollars. The mill I'm thinking of isn't nearly as powerful as regular ones but it'll get the job done. And Bridgeport's can't do all CNC mills can. It would take a CNC mill 10 minutes or less to make a sprocket, with a Bridgeport, I'd say it may take 3 weeks if your good. Good luck to what ever decision you decide upon.

And on the otherside, as said before, it takes tons of time and knowledge to setup a CNC.

I was working with a machinist at a shop that produces structural members for large buildings, and all they do is crank out like 100 of these mounting plates a day. For that, it's great. They program it once, then stick all the raw materials on pallets, and load it into the machine. He had a real good way of looking at it that I really found telling. He told me that it takes $2,000-$3000 to make the first part, then after that it's $.20 each.

Basically, CNC is for mass production, or extremely complex parts that simply arent possible on a manual mill.

My team was looking to develop a shifting transmission based on team 45's design this year (which unfortunately didnt pull together in time) and we did not have access to a CNC mill, which was "required". Working with the same machinist, we managed to make every single part which "required" CNC by hand, with no loss in performance, and perhaps a small loss in precision.

My point is, as others have said before, you can do almost anything on a manual mill if you're good enough.

Cory

[dlavery]

Phrontist and DanArgent -

As you can see, there is a strong consensus recommendation that you skip going to CNC for a while. If you want to bump up your manufacturing capabilities, consider a manual mill and/or lathe first. It will do the vast majority of the type of work you are likely to need for the FIRST competition, and provide a more gentle introduction to heavier fabrication techniques and capabilities.

That said, if you (or any of the other DC-area teams) are seriously interested in picking up a mill or lathe, consider a used production machine. There is a used machine tool auction held down near Fredricksburg late every spring. You can usually pick up a good piece of equipment there for about 10-15 cents on the dollar. Just be sure to take someone with you that knows what to look for, and to make sure that you don't get ripped off.

Also, consider attending a meeting of the Chesapeake Area Metalworking Society (CAMS). CAMS is populated with a bunch of retired machinists and metalworking hobbyists, and they are always happy to talk with new folks. They would be a perfect resource for you to learn about machine tool use, and how to make the best use of a new one that you pick up.

Actually, now that I think about it, it would probably be a good idea for a bunch of the DC-area teams to get together and put on a FIRST demonstration at a CAMS meeting. Let them know what we do, and see how many of their members might become team mentors. (slapping self in forehead) I should have thought about this a LONG time ago!

-dave

[Dick Linn]

Dave, where and when is this auction? I've just acquired a crummy $200 hobby mill/drill from a Homier sale to learn on and would eventually like to get a real vertical mill. I have seen some manual Webb vertical mills and Hardinge horizontal mills with vertical head attachments for in the neighborhood of $2,000 - $2,400., which works out to somewhere around a dollar a pound. Best of all, they are right here in Richmond, which saves a bit of trucking.

[eric195]

team 195 has a small CNC machine but only a few kids know how to use it because most of us are in a class called PLTW and we learn the CNC machine as Juniors. I as a freshman cant wait for Junior year. next year we will have a lot of kids that can use the CNC because our team consists of a lot of sophmores and they will no it next year.
we also have like 4 mills

[BoyWithCape195]

Originally Posted by eric195

team 195 has a small CNC machine but only a few kids know how to use it because most of us are in a class called PLTW and we learn the CNC machine as Juniors. I as a freshman cant wait for Junior year. next year we will have a lot of kids that can use the CNC because our team consists of a lot of sophmores and they will no it next year.
we also have like 4 mills

First, they are not asking teams if they have a CNC and know how to use it. Please post comments RELATED to other posts, not stupid stuff that comes out of your little mind. Please post things related to the question ASKED. As many people have said to you in the last 24 hours. THINK BEFORE YOU POST

[kid robusto]

eric195 please stop mouthing off. But anyways, I would seriously recommend finding a local shop that has a nice Bridgeport (or similar) and try it out. It does take more time to do, but will mostly likly save your whole team much time in trying to make stuff.

and as eric195 said, we do have 2 Mini Cnc's and 4 milling machines. these are all veryoild, and heavly abused. most of the decks are ~.05 off, and all the endmill the school has are broken. Even with with these Supermax's(that the brand,i laugh everytime i say it) we were able to make most of our robots parts. Tooks a fair amount of time,but alot less than trying to set up the CNC correctly.

[Stephen.Yanczura]

Originally Posted by kid robusto

eric195 please stop mouthing off. But anyways, I would seriously recommend finding a local shop that has a nice Bridgeport (or similar) and try it out. It does take more time to do, but will mostly likly save your whole team much time in trying to make stuff.

and as eric195 said, we do have 2 Mini Cnc's and 4 milling machines. these are all veryoild, and heavly abused. most of the decks are ~.05 off, and all the endmill the school has are broken. Even with with these Supermax's(that the brand,i laugh everytime i say it) we were able to make most of our robots parts. Tooks a fair amount of time,but alot less than trying to set up the CNC correctly.

I think (READ:"hope") the decks are not 50 thou off or we have some serious problems. I think at most the machines are off by +/-.002"ish and that could just be because none of us are machinists.

[coreyjon]

For the money, it would be better to invest in a used vetical mill, and a metal lathe. As the student Lead Machinist, 99% of my time spent machining parts was spent on these two machines. The use of a cnc mill wasn't really required, although it did speed up the time it would have taken to manually mill out a anti-back drive gear for the winch. Check out ebay. You'd be surprised what you can find on there.

[coreyjon]

Also, check out:

http://www.use-enco.com

They have brand new mills for under 5k, also new lathes under 4k.

The new lathe that we just got is:

http://www.useenco.com/CGI/INSRIT?PM...&PARTPG=INLMK3

They have a wide array of tooling, indicators, and other useful tools for a good price, if you want new.

Also, check out:

http://www.blueridgemachinery.com

They have a lot of different machines, Check out smithy in particular, while I would recommend a separate mill, and a separate lathe, they have 3-in-one machines that are a combination mill-drill-lathe. For the money, these things are great, they don’t take up much space, and they work well. Also, for the team on a budget, you save a lot of money but only buying one machine compared with 3. And the prices will shock you. (Like 240 3 phase).